Millions of individuals visit water parks every year to enjoy, among other attractions, various types of swimming pools. In particular, wave pools are generally known in the field as providing recreation involving artificially generated waves. The waves are traditionally formed by devices such as oscillating pressure caissons, periodic displacement devices, or devices for release of large volumes of water into the pool.
A new form of wave generation technology was disclosed in U.S. Pat. No. 5,833,393 to Carnahan et al., which is hereby incorporated by reference in its entirety. This technology is sometimes referred to as a wave cannon. A wave cannon transfers energy from the discharge of compressed air through a water-filled pipe and into a body of water to create swells or waves. Because of the nature of compressed gas, wave cannons may transfer large amounts of energy while providing unobtrusive infrastructure. This large amount of energy transfer improves the ability to produce larger waves.
In contrast, conventional wave generating technologies have been somewhat limited in the energy that can be imparted to the pool, based on the practical limits of size, mechanics, infrastructure, and cost. Thus, most wave pools are limited in size, with the larger wave pools being in the form of oversized swimming pools. Even with a smaller size, some wave pools incorporate special hydrodynamic features, such as narrowing waterways or wedge designs, to preserve or increase the wave height of these lower capacity waves.
The wave cannon may be scaled by size, number, orientation, and co-location. The wave cannon structure may be recessed, with structure located away from the body of water where an activity or water sport occurs. The structure of the wave generating device is thus removed from the area of activity and will not impair water sports. The small circular opening in the tubular chamber of a wave cannon permits novel orientations that enhance the production of large scale wave action similar to that in natural ocean environments. For example, a cluster of wave cannons at one end of a wave pool may generate waves sufficiently large for surfing.
A problem present in all conventional wave pools is the backwash caused by breaking waves. With smaller scale wave pools, this backwash has not been much of an issue. Simulated beaches or extensive shallows may be sufficient for smaller capacity breaking waves. However, the backwash of larger capacity waves may pose greater difficulties. The backwash of larger capacity waves may have the ability to draw individuals, floats, or surfboards into the paths of others located within the pool. The approach of a large capacity wave may then pose a safety hazard due to flotsam or individuals in the path of surfers or other individuals riding the wave.
Some conventional attempts to address the problems of this backwash have involved “lazy rivers” or water channels installed adjacent to the wave pool, and in which the intake and discharge of the lazy river is in fluid communication with the wave pool. Because a flow of water is desired from the wave breaking end of the pool to the wave generating end, some current may be created within the lazy river. This current has been created in some embodiments by permitting the breaking waves from the main pool to spill over a spillway or weir into the lazy river channel. Such pools are characterized by minor bottom shaping with largely dissipative beaches. In other cases, a current will be created within the lazy river channel by the installation of dedicated pumps. Some embodiments orient the inlet of the lazy channel and the dissipative slope of the simulated beach end so as to direct backwash into the mouth of the lazy river. Once established, the current is thus intended to draw some volume of water from the end of the wave pool in which waves break to the end of the wave pool where waves are formed, hopefully reducing the water backwashed to the deeper section of the wave pool.
The perimeter lazy river can reduce some of the backwash created in conventional wave pools by diverting some of the water. Of course, much of its effectiveness depends on the volumetric flow created by spill over or the volumetric flow rate of the pumps. However, it is impractical for wave pools having the large volume waves that are capable of being produced by the wave cannon. A greater reduction the backwash is required. The installation of pumps dedicated to generating a current in the lazy river provides additional infrastructure and cost. In addition, the slow current of a lazy river is inconsistent with the highly active sport of surfing.
Thus, conventional approaches to the reduction of wave pool backwash are not well suited to high capacity wave pools.